Image forming device

Abstract

To reduce the storage capacity of a carrier as compared with a case in which a wet type developer is used.SOLUTION: Image forming units 200 each include a photoconductor drum 11 as an example of an image holding body, and forms a toner image being an image to be transferred to a sheet 50 on the photoreceptor drum 11 by using a dry type developer. In other words, the image forming units 200 each form the toner image to be transferred to the sheet 50 on the photoreceptor drum 11 by using a powder-like developer. The developer is formed of a powder-like dry type carrier and powder-like dry type toner. The image forming units 200 each form the toner image on the photoreceptor drum 11 by using the powder-like dry type carrier and the powder-like dry type toner.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] As a prior art, Patent Document 1 discloses a liquid developing device that includes a developing tank in which liquid toner is stored, a scooping roller that scoops up the liquid toner from the developing tank, and a developing roller that supplies the liquid toner scooped up by the scooping roller to the surface of a photosensitive drum. Furthermore, Patent Document 2 discloses a configuration in which a plurality of developing units for handling the respective colors of YMCK are provided, and a developer container is disposed in each developing unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-264121 A [Patent Document 2] JP 2007-171346 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to reduce the carrier storage volume compared to when a wet developer is used. [Means for solving the problem]

[0005] The invention described in claim 1 is An image forming apparatus for forming an image on a recording medium,at least five image forming units each including an image carrier and using a dry toner to form an image to be transferred to a recording medium on the image carrier; a developing device provided in each of the at least five image forming units to which a dry toner and a dry carrier are supplied, the developing device including a dry toner attachment portion having a length equal to or longer than the long side of an A3 size and to which the dry toner is attached, and the developing device attaches the dry toner attached to the dry toner attachment portion to the image carrier; a toner supply mechanism that is attached to the image forming apparatus and transports dry toner from a toner storage container that stores dry toner to the developing device and supplies the dry toner to the developing device; and a carrier supply mechanism that is attached to the image forming apparatus and transports dry carrier from a carrier storage container that stores a dry carrier to the developing device and supplies the dry carrier to the developing device, wherein an amount of dry toner supplied to the developing device is greater than an amount of dry carrier supplied to the developing device, and the dry toner discharged from a toner discharge section provided in the toner storage container is discharged from a toner discharge section provided in the toner storage container. the path along which the dry carrier discharged from the carrier discharge portion provided in the carrier storage container travels when heading toward the developing device is from a location where the toner discharge portion is provided toward the upstream side in the mounting direction when the toner storage container is mounted, and then travels downstream in the mounting direction to reach the developing device; and the path along which the dry carrier discharged from the carrier discharge portion provided in the carrier storage container travels when heading toward the developing device is not from a location where the carrier discharge portion is provided toward the downstream side in the mounting direction when the toner storage container is mounted, but travels downstream in the mounting direction to reach the developing device. An image forming apparatus. The invention described in claim 2 is The image forming device of claim 1, wherein the carrier storage container and the toner storage container are configured to be individually mounted on the image forming device, and when comparing the length of the toner storage container in the mounting direction, the carrier storage container is shorter than the toner storage container. The invention described in claim 3 is The image forming apparatus of claim 2, wherein when the carrier storage container and the toner storage container are mounted in the image forming apparatus, an end of the carrier storage container that is located downstream in the mounting direction is located upstream in the mounting direction of an end of the toner storage container that is located downstream in the mounting direction. Claim 4 The invention described in is an image forming apparatus as described in claim 1, further comprising a transfer unit that transfers an image formed by the image forming unit to a recording medium, and an inversion mechanism that inverts the recording medium having an image transferred to one side by the transfer unit and supplies the recording medium to the transfer unit. Claim 5 The invention described in before 2. The image forming apparatus according to claim 1, wherein a volume of a space in the carrier supply mechanism through which the dry carrier passes is smaller than a volume of a space in the toner supply mechanism through which the dry toner passes. The invention described in claim 6 is pieces The image forming apparatus of claim 1, wherein the sum of the amount of dry carrier supplied per unit time to each of the developing devices and the amount of dry carrier discharged per unit time from each of the developing devices is multiplied by the number of the image forming units installed, is smaller than the amount of dry toner consumed per unit time when an image is formed in each of the image forming devices multiplied by the number of the image forming units installed. Claim 7 The invention described in toner Containment vessel The above When comparing the cross-sectional areas in a plane perpendicular to the mounting direction, dry method Career The route through which The cross-sectional area is dry method toner The route through which 2. The image forming apparatus according to claim 1, wherein the cross-sectional area is smaller than the cross-sectional area of ​​the image forming apparatus. Claim 8 The invention described in the item (1) is the toner supply mechanism The developing device is configured to drop dry toner onto the developing device. supply death, the toner supply mechanism is provided with a toner dropping section through which the dry toner drops toward the developing device; The carrier supply mechanism teeth ,lead The dry carrier is dropped from directly above into the developing device. The carrier supply mechanism is provided with a carrier drop section where the dry carrier falls toward the developing device, and the carrier drop section is located directly above the toner drop section, and the falling dry carrier reaches the toner drop section. The image forming apparatus according to claim 1. Claim 9 The invention described in Attached to the image forming apparatus The carrier housing container The bottom of the vertical direction is The image forming apparatus is The toner storage container 2. The image forming apparatus according to claim 1, wherein the lowermost portion of the image forming apparatus is located vertically below the lowermost portion of the image forming apparatus in the vertical direction. Effect of the Invention

[0006] Claim 1 ~3 According to the invention, the volume of the carrier that can be accommodated can be made smaller than when a wet developer is used. Claim 4 According to the invention, an image having a length equal to or greater than the length of the long side of A3 size can be formed on both sides of a recording medium. Claim 5 According to this invention, the image forming apparatus can be made smaller than when the volume of the space in the portion of the carrier supply mechanism through which the dry carrier passes is larger than the volume of the space in the portion of the toner supply mechanism through which the dry toner passes. According to the invention of claim 6, the mechanism required for supplying and discharging dry toner can be made smaller than when the value obtained by multiplying the sum of the amount of dry carrier supplied per unit time when it is supplied to each developing device and the amount of dry carrier discharged per unit time when it is discharged from each developing device by the number of installed image forming units is greater than the value obtained by multiplying the amount of dry toner consumed per unit time when an image is formed in each image forming unit by the number of installed units. Claim 7 According to the invention, The route that the dry carrier takes The cross-sectional area is The path that dry toner takes Compared to when it is larger than the cross-sectional area, Path taken by dry carriers This can prevent the image forming apparatus from becoming large due to the above. Claim 8 According to the invention, the carrier supply mechanism The dry toner can be broken down using a dry carrier provided by the. Claim 9 According to the invention, a toner container container The carrier is stored vertically below the position where the container It can be attached and detached. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 illustrates an image forming apparatus. [Diagram 2] FIG. [Diagram 3] 3 is a view of the developer supply device as seen from the direction III in FIG. 2. [Figure 4] 4 is a view of the developer supply device as seen from a direction IV in FIG. 2. [Diagram 5] 5 is a cross-sectional view taken along line VV in FIG. 4. [Figure 6] 6 is a cross-sectional view taken along line VI-VI in FIG. 4. [Figure 7] FIG. 7 is an enlarged view of part VII in FIG. [Figure 8] FIG. 2 is a diagram illustrating a developing device. [Figure 9] 9 is a diagram of the developing sleeve as viewed from the direction indicated by the arrow IX in FIG. 8. [Figure 10] FIG. 2 is a schematic diagram illustrating functions of the image forming apparatus. [Figure 11] FIG. 13 is a diagram illustrating another example of the configuration of an image forming apparatus. [Figure 12] FIG. 13 is a diagram illustrating another example of the configuration of an image forming apparatus. [Figure 13] FIG. 13 is a diagram illustrating another example of the configuration of an image forming apparatus. [Figure 14] FIG. 13 is a diagram illustrating another example of the configuration of an image forming apparatus. [Figure 15] FIG. 13 is a diagram illustrating another example of the configuration of an image forming apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram showing an image forming apparatus 100 according to the present embodiment. The image forming apparatus 100 is of an intermediate transfer type, known as a tandem type. This image forming apparatus 100 is provided with at least five image forming units 200 that form images to be transferred onto paper 50, which is an example of a recording medium. The number of image forming units 200 is preferably five or more, and in this embodiment, the number of image forming units 200 is six.

[0009] Each of the image forming units 200 includes a photoconductor drum 11 as an example of an image carrier, and uses a dry developer to form a toner image, which is an image to be transferred to paper 50, on this photoconductor drum 11. In other words, each of the image forming units 200 uses a powder developer to form a toner image, which is to be transferred to paper 50, on this photoconductor drum 11. The developer in this embodiment is composed of a powdered dry carrier and a powdered dry toner, and each of the image forming units 200 uses the powdered dry carrier and the powdered dry toner to form a toner image on the photosensitive drum 11. In this way, when a dry developer is used, the carrier capacity can be made smaller than when a wet developer is used.

[0010] The six image forming units 200 form toner images on the photoconductor drums 11 using different types of dry toner. Specifically, in this embodiment, of the six image forming units 200, four image forming units 200 form toner images using dry toners of the basic colors of yellow, magenta, cyan, and black. The remaining two image forming units 200 form toner images using dry toners of special colors such as clear, white, gold, silver, pink, green, and orange.

[0011] The types of dry toner are not limited to those mentioned above, but include magnetic dry toner and conductive dry toner, and also include dry toner that emits light when irradiated with light such as ultraviolet light or infrared light. The "different types of dry toners" are not limited to dry toners having different colors, but also include dry toners having different functions and properties. For example, even if two dry toners have the same color, if one is a magnetic dry toner and the other is a conductive dry toner, the two dry toners can be said to be of different types.

[0012] In this embodiment, a plurality of image forming units 200 using dry toner are provided, but in addition to these image forming units 200, other image forming units 200 may be provided. Specifically, for example, an image forming unit 200 that forms a toner image using only dry toner without using a dry carrier, or an image forming unit 200 that forms an image by an inkjet method may be additionally provided.

[0013] The image forming apparatus 100 is also provided with an intermediate transfer belt 15 and a primary transfer section 10 for transferring the toner images formed in the image forming sections 200 onto the intermediate transfer belt 15 . Furthermore, the image forming apparatus 100 is provided with a secondary transfer section 20 for transferring the toner image transferred onto the intermediate transfer belt 15 onto a sheet of paper 50 .

[0014] The image forming apparatus 100 is also provided with a fixing device 60 that fixes the toner image transferred onto the paper 50 . Furthermore, the image forming apparatus 100 is provided with a control unit 40 that includes a CPU that executes a program and controls each unit within the image forming apparatus 100 . Image forming apparatus 100 is also provided with a UI (User Interface) 45, which is configured with a display panel or the like and receives instructions from a user and displays information to the user.

[0015] Each of the image forming sections 200 is provided with a developing device 14. Also, each of the image forming sections 200 is provided with a developer replenishing device 70 that replenishing the developing device 14 with developer. The developing device 14 develops the electrostatic latent image on the photoconductor drum 11 into a visible image using dry toner. The developer replenishing device 70 replenishing developer to the developing device 14. The developer is composed of a magnetic dry carrier and a dry toner, and the developer replenishing device 70 replenishing the developing device 14 with the dry carrier and the dry toner. In this example, the dry carrier has a positive charge polarity and the dry toner has a negative charge polarity.

[0016] In each of the image forming units 200, a photoconductor drum 11, which is an example of an image carrier, rotates in the direction of arrow A. Each image forming unit 200 is provided with a charger 12 that charges the photoconductor drum 11, and a laser exposure device 13 as an example of an exposure device that forms an electrostatic latent image on the photoconductor drum 11. The exposure device may be configured with a device having a plurality of light sources such as LEDs. In FIG. 1, the exposure beam from the laser exposure device 13 is indicated by the symbol Bm.

[0017] FIG. 8 is a diagram illustrating the developing device 14. As shown in FIG. The developing device 14 includes a container 141 that contains a developer. The container 141 is formed of a container housing 142 made of resin, for example. The developing device 14 is disposed so as to extend in a direction from the front side to the rear side of the image forming apparatus 100 (a direction perpendicular to the plane of the paper in FIG. 1).

[0018] The housing 142 has an opening 143 at a location facing the photoconductor drum 11 (see FIG. 1). In this opening 143, a developing roll 145 for depositing a developer onto the surface of the photosensitive drum 11 is provided. The developing roll 145 is formed in a cylindrical shape, and is disposed so as to extend along a direction from the front side to the rear side of the image forming apparatus 100 (a direction perpendicular to the paper surface of FIG. 1).

[0019] The developing roll 145 is provided with a developing sleeve 145A which is formed of a cylindrical body and is driven to rotate, and a magnet roll 145B which is disposed inside the developing sleeve 145A. The developing sleeve 145A, which is an example of a dry toner adhesion portion, is made of a metal such as SUS.

[0020] FIG. 9 is a diagram of the developing sleeve 145A as viewed from the direction indicated by the arrow IX in FIG. As shown in FIG. 9, the developing sleeve 145A of this embodiment has an axial length L that is equal to or greater than the long side of an A3 size sheet. More specifically, the long side of the A3 size is 420 mm, and the developing sleeve 145A of this embodiment has an axial length L of 420 mm or more.

[0021] The developing sleeve 145A rotates in the direction of the arrow 8A in Fig. 8. In other words, the developing sleeve 145A rotates so that the portion located inside the containing portion 141 moves upward. Furthermore, in this embodiment, the developing sleeve 145A and the photoconductor drum 11 rotate so that they move in the same direction at the opposing portion TK (see FIG. 1) between the developing roll 145 and the photoconductor drum 11. In this embodiment, the photoconductor drum 11 also has an axial length that is equal to or longer than the long side of the A3 size. As shown in FIG. 8, the developing device 14 is provided with a first transport member 146 and a second transport member 147 for transporting the developer.

[0022] The first transport member 146 and the second transport member 147 are provided on the opposite side to the side on which the photoconductor drum 11 (see FIG. 1) is installed, with the developing roll 145 sandwiched therebetween. Furthermore, in this embodiment, a first conveying member 146 is provided on the side closer to the photosensitive drum 11, and a second conveying member 147 is provided on the side farther from the photosensitive drum 11.

[0023] The first transport member 146 is disposed so as to extend along a direction from the front side to the rear side of the image forming apparatus 100, and transports the developer, for example, to the rear side of the image forming apparatus 100. The second transport member 147 is also disposed so as to extend in a direction from the front side to the rear side of the image forming apparatus 100, and transports the developer to the front side of the image forming apparatus 100. In this embodiment, the first conveying member 146 and the second conveying member 147 also have an axial length that is equal to or greater than the length of the long side of the A3 size.

[0024] Furthermore, in this embodiment, the space inside the storage housing 142 is divided by a partition wall 148, and inside the storage housing 142, there is a first space 148A located on the photosensitive drum 11 side, and a second space 148B located on the side away from the photosensitive drum 11. In this embodiment, a first conveying member 146 is installed in the first space 148A, and a second conveying member 147 is installed in the second space 148B.

[0025] The partition wall 148 is not formed over the entire area in the longitudinal direction of the housing 142. The partition wall 148 is not provided on the rear and front sides of the housing 142. At both ends in the longitudinal direction of the housing 142, there are non-formed portions where the partition wall 148 is not formed. As a result, in this embodiment, the developer circulates inside the developing device 14.

[0026] Specifically, in this embodiment, the developer in the first space 148A is transported by the first transport member 146 toward the back side of the paper surface of FIG. Then, when the developer reaches the end portion on the far side of the accommodating housing 142, it passes through the non-formed portion and moves into the second space 148B.

[0027] The developer moved to the second space 148B is transported toward the front side of the paper surface of Fig. 8 by the second transport member 147. Then, this developer passes through a non-forming portion provided at the end portion on the front side of the accommodating housing 142 and moves to the first space 148A. Thereafter, this movement of the developer is repeated, and the developer circulates inside the developing device 14. In this embodiment, the developer is agitated by this circulatory movement. In this embodiment, the length of the housing 142 in the same direction as the axial length of the developing sleeve 145A is equal to or greater than the long side of the A3 size.

[0028] Furthermore, the developing device 14 is provided with a layer regulating portion 151 above the developing roll 145. The layer regulating portion 151 is disposed with a gap between it and the developing roll 145. The layer regulating section 151 regulates the movement of a portion of the developer adhering to the surface of the developing roll 145, so that the thickness of the developer adhering to the surface of the developing roll 145 becomes a predetermined thickness.

[0029] Further, the developing device 14 is provided below the developing roll 145 with a lower opposing portion 152 opposing the developing roll 145 . In this embodiment, an opening 143 is provided between the layer regulating portion 151 and the lower facing portion 152, and a developing roll 145 is installed in this opening 143.

[0030] The magnet roll 145B is provided with seven magnetic poles N1 to N4 (north poles) and S1 to S3 (south poles) arranged in the circumferential direction of the magnet roll 145B. The magnetic pole N3 (pickup pole) attracts the developer transported by the first transport member 146. As a result, in this embodiment, the developer adheres to the surface of the developing sleeve 145A, which is an example of a dry toner adhesion portion. The magnetic pole S2 (trimming pole), together with the layer regulating portion 151, regulates the thickness of the developer attached to the surface of the developing roll 145 to a predetermined thickness.

[0031] The magnetic poles S3, N2, and N1 function as transport poles, and move the developer on the developing sleeve 145A downstream in the rotation direction of the developing sleeve 145A. The magnetic pole S1 (developing pole) forms developer spikes together with the adjacent magnetic pole N1. In this embodiment, dry toner contained in the developer spikes moves to the surface of the photoconductor drum 11 (see FIG. 1), and the dry toner adheres to the photoconductor drum 11, which is an example of an image carrier.

[0032] As a result, development is carried out and a toner image is formed on the photosensitive drum 11. This toner image is temporarily held by the photosensitive drum 11 and is then moved to the primary transfer portion 10 by the rotating photosensitive drum 11 . The magnetic pole N4 (pick-off pole) forms a repulsive magnetic field together with the adjacent magnetic pole N3, and causes the developer adhering to the surface of the developing sleeve 145A to separate from the developing sleeve 145A. In this embodiment, the length of the layer regulating portion 151, the lower opposing portion 152, and the opening 143 in the same direction as the axial length of the developing sleeve 145A described above is longer than the long side of the A3 size.

[0033] Referring again to FIG. 1, the image forming apparatus 100 will be further described. Each image forming section 200 is provided with a primary transfer roll 16 that transfers a toner image formed on a photoconductor drum 11 onto an intermediate transfer belt 15 in a primary transfer section 10 . Further, each of the image forming units 200 is provided with a drum cleaner 17 for removing developer remaining on the photosensitive drum 11.

[0034] The intermediate transfer belt 15 is circulated at a predetermined speed in the direction of arrow B shown in FIG. 1 by a drive roll 31 driven by a motor (not shown). The primary transfer unit 10 includes a primary transfer roll 16 disposed opposite the photoconductor drum 11 with an intermediate transfer belt 15 sandwiched therebetween. The toner images on the photoconductor drums 11 are electrostatically attracted to the intermediate transfer belt 15 in sequence, and superimposed toner images are formed on the intermediate transfer belt 15.

[0035] The secondary transfer unit 20 as an example of a transfer unit includes a secondary transfer roll 22 arranged on the outer surface side of the intermediate transfer belt 15 and a backup roll 25 arranged on the inner surface side of the intermediate transfer belt 15 . In this embodiment, in the secondary transfer section 20 , the toner image formed by the image forming section 200 and transferred onto the intermediate transfer belt 15 is transferred onto the paper 50 conveyed to the secondary transfer section 20 .

[0036] Furthermore, in this embodiment, a reversing mechanism 900 for reversing the paper 50 is provided. The reversing mechanism 900 reverses the sheet 50 , one side of which has a toner image transferred thereon by the secondary transfer unit 20 , and supplies the sheet 50 to the secondary transfer unit 20 again. As a result, in this embodiment, toner images can be formed on both sides of the paper 50.

[0037] Specifically, in this embodiment, the reversing mechanism 900 reverses the paper 50 by feeding the paper 50 after passing through the fixing device 60 to a branch path R2 branched from the paper transport path R1. Specifically, after the paper 50 passes through the branching section BP, the reversing mechanism 900 transports the paper 50 in the opposite direction, and further feeds the paper 50 into the branch path R2. This branch path R2 merges with the paper transport path R1 upstream of the secondary transfer unit 20. As a result, in this embodiment, the paper 50 in an inverted state is again supplied to the secondary transfer unit 20. In this case, a toner image is formed not only on one side of the paper 50 but also on the other side, so that a toner image is formed on both sides of the paper 50.

[0038] In the image forming apparatus 100 of this embodiment, a toner image is formed on a large size paper 50 such as A2 size, and toner images can be formed on both sides of the paper 50. In this case, for example, it is possible to easily form a large notice that can be attached to glass or the like and can be viewed from both sides. Furthermore, in the case where multiple paper products are made by cutting out and assembling the paper 50 after the image has been formed, if the paper 50 on which the toner image is formed is itself large, as in this embodiment, the efficiency of paper product production can be improved. Specifically, the number of paper products that can be made from one sheet of paper 50 can be increased, and the efficiency of paper product production can be improved.

[0039] The flow of processing performed by the image forming apparatus 100 will be described. The image forming apparatus 100 receives image data output from, for example, an image reading device (not shown), and performs image processing on the image data. As a result, image data corresponding to each of the multiple image forming units 200 is generated. Specifically, for example, image data for four colors, yellow, magenta, cyan, and black, and image data for a special color are generated. The generated image data is output to a laser exposure device 13 provided in the image forming unit 200.

[0040] The laser exposure device 13 irradiates the photoconductor drum 11 with an exposure beam Bm emitted from, for example, a semiconductor laser in accordance with input image data. In this embodiment, the surface of each photoconductor drum 11 is charged by the charger 12, and then the surface is subjected to scanning exposure by the laser exposure device 13. As a result, an electrostatic latent image is formed on the surface of the photoconductor drum 11. Next, a developing process is carried out by the developing device 14, and a toner image is formed on the photoconductor drum 11. This toner image is transferred onto the intermediate transfer belt 15 in the primary transfer section 10.

[0041] After the toner image is transferred onto the intermediate transfer belt 15, the movement of the intermediate transfer belt 15 moves the toner image to the secondary transfer unit 20. At this time, the paper 50 from the first paper storage unit 53 or the second paper storage unit 54 is transported to the secondary transfer unit 20 by the transport rolls 52 or the like. Then, the toner images on the intermediate transfer belt 15 are electrostatically transferred all at once onto a sheet 50 in the secondary transfer section 20 .

[0042] Thereafter, the paper 50 onto which the toner image has been transferred is peeled off from the intermediate transfer belt 15 and conveyed to a conveyor belt 55. The conveyor belt 55 conveys the paper 50 to a fixing device 60. The paper 50 conveyed to the fixing device 60 is heated and pressurized by the fixing device 60. As a result, the toner image on the paper 50 is fixed to the paper 50. Then, the paper 50 is discharged from the image forming apparatus 100.

[0043] When toner images are formed on both sides of the paper 50, after the paper 50 passes through the fixing device 60, the paper 50 is supplied again to the secondary transfer unit 20 via a branch route R2. Then, in the secondary transfer section 20, the toner image is transferred to the other side of the paper 50. Thereafter, the paper 50 passes through the fixing device 60 again, and the toner image transferred to the other side is fixed to the paper 50.

[0044] (Configuration of Developer Supply Device) Next, the developer supplying device 70 will be described. Fig. 2 is a perspective view of the developer supply device 70. In Fig. 2, the lower right is the front side of the image forming apparatus 100, and the upper left is the rear side of the image forming apparatus 100. In other words, in Fig. 2, the lower right is the front side of the image forming apparatus 100, and the upper left is the rear side of the image forming apparatus 100. Fig. 3 is a view of developer supply device 70 as viewed from direction III in Fig. 2. Fig. 4 is a view of developer supply device 70 as viewed from direction IV (i.e., from the front) in Fig. 2. Fig. 5 is a cross-sectional view at portion VV in Fig. 4. Fig. 6 is a cross-sectional view at portion VI-VI in Fig. 4. Fig. 7 is an enlarged view of portion VII in Fig. 6.

[0045] As shown in FIG. 2, the developer supply device 70 has two toner containers 630 for containing dry toner, and a toner dispenser 82. In this embodiment, a toner cartridge 81 that contains dry toner is installed in each of the toner containers 630. The two toner cartridges 81 have the same configuration. The toner dispenser 82, which is an example of a toner replenishing section, receives dry toner from each of the toner storage sections 630, and supplies the dry toner to the developing device 14 (see FIG. 1).

[0046] The toner storage unit 630 is provided at a location separate from the developing device 14 (see FIG. 1). In this embodiment, dry toner newly supplied from outside image forming apparatus 100 is stored in toner storage unit 630 . Specifically, in this embodiment, new dry toner is supplied to toner storage unit 630 by mounting toner cartridge 81, which is an example of a storage container that stores dry toner, on toner storage unit 630.

[0047] In this embodiment, all parts of the toner cartridge 81 are housed inside the image forming apparatus 100, but this is not limited thereto, and a part of the toner cartridge 81 may be exposed to the outside of the image forming apparatus 100. Further, the toner containing portion 630 does not necessarily have toner cartridge 81 attached thereto, and the toner containing portion 630 may be an accommodation chamber for accommodating dry toner. In this case, for example, the user manually puts only dry toner into the toner container 630 . Alternatively, for example, a transfer container used for transferring dry toner is temporarily connected to the toner storage chamber, and the dry toner is automatically transferred from the transfer container to the toner storage chamber. After the dry toner is transferred from the transfer container to the toner storage chamber, the transfer container is removed.

[0048] The developer supply device 70 is also provided with a carrier container 530 that contains a dry carrier, and a carrier dispenser 92 . The carrier dispenser 92, which is an example of a carrier replenishing unit, receives the dry carrier from the carrier accommodating unit 530 and supplies the dry carrier to the developing device 14 (see FIG. 1).

[0049] In this embodiment, a carrier cartridge 91 that accommodates a dry carrier therein is installed in the carrier accommodating portion 530. In this example, unlike the toner cartridge 81, one carrier cartridge 91 is provided in the developer replenishing device . A carrier dispenser 92, which is an example of a carrier replenishing section, receives a dry carrier from a carrier cartridge 91 provided in a carrier accommodating section 530, and supplies the dry carrier to the developing device 14 (see FIG. 1).

[0050] The carrier accommodating portion 530 is provided at a location separate from the developing device 14 (see FIG. 1). In this embodiment, a dry carrier newly supplied from outside the image forming apparatus 100 is accommodated in the carrier accommodating section 530 . Specifically, in this embodiment, a carrier cartridge 91, which is an example of a container that contains a dry carrier, is attached to the carrier container 530, whereby new dry carrier is supplied to the carrier container 530.

[0051] In this embodiment, all parts of the carrier cartridge 91 are housed inside the image forming apparatus 100, but this is not limited thereto, and a part of the carrier cartridge 91 may be exposed to the outside of the image forming apparatus 100. Further, the carrier accommodating section 530 does not necessarily have to have the carrier cartridge 91 attached thereto, and the carrier accommodating section 530 may be an accommodating chamber for accommodating a dry carrier. In this case, for example, the user manually places only the dry carrier into the carrier receiving section 530 . Alternatively, for example, a transport container used for transporting the dry carrier is temporarily connected to the carrier housing chamber, and the dry carrier is automatically transferred from the transport container to the carrier housing chamber. After the dry carrier is transferred from the transport container to the carrier housing chamber, the transport container is removed.

[0052] Each of the toner cartridges 81 is disposed so as to extend in the front-rear direction of the image forming apparatus 100. Each of the toner cartridges 81 has a cylindrical shape. Each of the toner cartridges 81 is detachably attached to the main body of the developer supply device 70. Specifically, the toner cartridge 81 is removed from the developer supply device 70 by pulling it out toward the front of the developer supply device 70. The toner cartridge 81 is attached to the developer supply device 70 by pushing it toward the rear of the developer supply device 70. Specifically, the direction indicated by the arrow 2A is the direction in which the toner cartridge 81 is removed, and the direction indicated by the arrow 2B is the direction in which the toner cartridge 81 is installed.

[0053] As shown in FIG. 5, inside the toner cartridge 81, a toner agitating member 811 for agitating the dry toner is provided. The toner agitating member 811 is rotationally driven by a drive motor (not shown) and agitates the dry toner inside the toner cartridge 81. The toner agitating member 811 also transports the dry toner from the front to the rear of the toner cartridge 81.

[0054] The transport direction of the dry toner inside the toner cartridge 81 is aligned with the mounting / removal direction when the toner cartridge 81 is mounted / removed. In this embodiment, "along the mounting / removal direction" does not necessarily have to be parallel to the mounting / removal direction, and it is sufficient that the transport direction at least has a component in the mounting / removal direction. Further, the toner cartridge 81 has a toner discharge section 813. The dry toner transported by the toner stirring member 811 is discharged from the toner discharge section 813 and supplied to the toner dispenser 82. More specifically, the dry toner is supplied to a toner reserve tank 83 provided in the toner dispenser 82. The toner discharge portion 813 is provided at the rear of the toner cartridge 81. Moreover, the toner discharge portion 813 is provided on a lower surface of the toner cartridge 81 that faces the toner reserve tank 83.

[0055] 2, the toner dispenser 82 is provided with two toner reserve tanks 83 for storing the dry toner received from the toner cartridge 81. The two toner reserve tanks 83 have the same configuration. As shown in FIG. 3, the toner dispenser 82 is provided with a toner transport unit 84 that receives dry toner from two toner reserve tanks 83 and transports the dry toner toward the developing device 14 (see FIG. 1). As shown in FIG. 6, the toner dispenser 82 is provided with a toner input section 85 that inputs the dry toner transported through the toner transport section 84 into the developing device 14.

[0056] 2, each of the toner reserve tanks 83 extends in the front-rear direction of the developer supply device 70 and has a box-like shape. As shown in FIG. 5, inside the toner reserve tank 83, a toner transport member 831 is provided for transporting the dry toner while stirring it.

[0057] The toner transport member 831 is rotationally driven by a drive motor (not shown), and agitates the dry toner inside the toner reserve tank 83. The toner transport member 831 also transports the dry toner from the rear of the toner reserve tank 83 to the front. In this embodiment, the direction in which the dry toner is transported in the toner reserve tank 83 is opposite to the direction in which the dry toner is transported in the toner cartridge 81 . In this embodiment, the direction in which the dry toner is transported in the toner reserve tank 83 is the same as the direction in which the toner cartridge 81 is attached and detached.

[0058] An example of the toner transport member 831 is a transport member having a rotating shaft extending in the front-rear direction of the toner reserve tank 83 and a blade portion formed in a spiral shape around the rotating shaft. 5, in this embodiment, a toner detector 834 is provided inside the toner reserve tank 83. The toner detector 834 detects whether or not dry toner is present inside the toner reserve tank 83. Toner detection unit 834 is provided at a position closer to toner receiving unit 832 than toner discharge unit 833. For toner detection unit 834, known technology such as a magnetic sensor, a piezoelectric sensor, or a photoelectric sensor is used.

[0059] As shown in FIG. 5, the toner reserve tank 83 is provided with a toner receiving portion 832 that receives the dry toner discharged from the toner discharging portion 813 of the toner cartridge 81. Further, the toner reserve tank 83 is provided with a toner discharge portion 833 that discharges the dry toner transported by the toner transport member 831 . The dry toner discharged from toner discharge unit 833 is supplied to toner transport unit 84. Specifically, the dry toner discharged from toner discharge unit 833 is supplied to toner junction 841 (see FIG. 4) provided in toner transport unit 84.

[0060] The toner receiving portion 832 shown in FIG. 5 is provided at a position opposite to the toner discharging portion 813 of the toner cartridge 81. The toner receiving portion 832 is provided behind the toner reserve tank 83. The toner receiving portion 832 is provided on the upper surface of the toner reserve tank 83. On the other hand, the toner discharge portion 833 is provided in front of the toner reserve tank 83. The toner discharge portion 833 is also provided on the lower surface of the toner reserve tank 83. The toner discharge unit 833 discharges the dry toner to a toner junction 841 (see FIG. 4).

[0061] As shown in FIG. 2, the toner transport section 84 is provided with a toner junction 841 where the dry toner discharged from the two toner reserve tanks 83 join together, and a toner transport path 842 which transports the dry toner that has passed through the toner junction 841 toward the toner input section 85. The toner transport path 842 extends in the front-rear direction of the developer supply device 70. The toner transport path 842 has a cylindrical shape. As shown in FIG. 6, a toner transport member 843 that transports the dry toner while stirring it is provided inside the toner transport path 842.

[0062] Toner transport member 843 is rotationally driven by a drive motor (not shown), and agitates dry toner inside toner transport path 842. Toner transport member 843 also transports dry toner from the front of toner transport path 842 to the rear. In this embodiment, the direction in which the dry toner is transported in the toner transport section 84 is aligned with the mounting and detaching direction in which the toner cartridge 81 (see FIG. 2) is mounted to and detached from the developer supply device 70.

[0063] A toner input unit 85 shown in FIG. 6 inputs the dry toner conveyed through a toner conveying path 842 into the developing device 14 (see FIG. 1). In this embodiment, the toner dispenser 85 is located vertically above the developing device 14. The toner dispenser 85 drops the dry toner downward by gravity, and dispenses the dry toner into the developing device 14.

[0064] 2, the carrier cartridge 91 is disposed so as to extend in the front-rear direction of the developer supply device 70. The carrier cartridge 91 has a cylindrical shape. The carrier cartridge 91 is detachable from the main body of the developer supply device 70 in the front-rear direction of the developer supply device 70 . Specifically, the carrier cartridge 91 is removed from the developer supply device 70 by pulling it out toward the front of the developer supply device 70. The carrier cartridge 91 is attached to the developer supply device 70 by pushing it toward the rear of the developer supply device 70.

[0065] In this embodiment, the length of the carrier cartridge 91 in the mounting / removal direction of the carrier cartridge 91 is shorter than the length of the toner cartridge 81 in the mounting / removal direction of the toner cartridge 81. In other words, in this embodiment, the length of the carrier containing portion 530 is shorter than the length of the toner containing portion 630 when comparing the lengths in the mounting direction of the toner cartridge 81, which is an example of a containing container.

[0066] In this embodiment, the location where the carrier cartridge 91 is attached is a carrier accommodating section 530 that accommodates a dry carrier. In this embodiment, a carrier cartridge 91 is attached to the carrier accommodating section 530, whereby new dry carrier is supplied to the carrier accommodating section 530. In this embodiment, the location where the toner cartridge 81 is attached serves as a toner storage section 630 that stores dry toner. In this embodiment, when a toner cartridge 81 is attached to the toner containing unit 630, new dry toner is supplied to the toner containing unit 630.

[0067] In this embodiment, when comparing the lengths of the toner cartridge 81 in the mounting direction, the length of the carrier containing section 530 is shorter than the length of the toner containing section 630 . In addition, in this embodiment, as shown in FIG. 3, the rear end portion (hereinafter, sometimes referred to as the “rear end”) of the carrier cartridge 91 is located in front of the rear end of the toner cartridge 81 in the developer supply device 70.

[0068] As shown in FIG. 6, inside the carrier cartridge 91, a carrier stirring member 911 for stirring the dry carrier is provided. The carrier stirring member 911 is rotated by a driving motor (not shown). The carrier agitation member 911 agitates the dry carrier inside the carrier cartridge 91. In addition, the carrier agitation member 911 transports the dry carrier from the front to the rear of the carrier cartridge 91. In this embodiment, the transport direction of the dry carrier in the carrier cartridge 91 is aligned with the mounting and detaching direction when the carrier cartridge 91 is mounted and detached.

[0069] The carrier cartridge 91 has a carrier discharge portion 913 . The dry carrier discharged from the carrier discharge part 913 is supplied to the carrier dispenser 92. Specifically, the dry carrier discharged from the carrier discharge part 913 is supplied to a carrier reserve tank 93 provided in the carrier dispenser 92. The carrier discharge portion 913 is provided on the outer circumferential surface of the carrier cartridge 91. The carrier discharge portion 913 is also provided on the rear and lower surface of the carrier cartridge 91.

[0070] The carrier dispenser 92 is provided with a carrier reserve tank 93 that stores the dry carrier received from the carrier cartridge 91 . The carrier dispenser 92 is provided with a carrier dispenser 95 that dispenses the dry carrier contained in the carrier reserve tank 93 into the developing device 14 .

[0071] 2, the carrier reserve tank 93 is disposed so as to extend in the front-rear direction of the developer supply device 70. The carrier reserve tank 93 is formed to be elongated and has a cylindrical shape. As shown in FIG. 4, the carrier reserve tank 93 is provided vertically below the carrier cartridge 91. In this embodiment, the volume of the carrier reserve tank 93 is smaller than the volume of the toner reserve tank 83 .

[0072] In this embodiment, the cross-sectional area of ​​the carrier reserve tank 93 is smaller than the cross-sectional area of ​​the toner reserve tank 83 . More specifically, when comparing the cross-sectional areas in a plane perpendicular to the mounting direction of the toner cartridge 81, the cross-sectional area of ​​the carrier reserve tank 93 is smaller than the cross-sectional area of ​​the toner reserve tank 83.

[0073] As shown in FIG. 6, inside the carrier reserve tank 93, a carrier transport member 931 is provided which transports the dry carrier while stirring it. The carrier transport member 931 is rotated by a drive motor (not shown). The carrier transport member 931 agitates the dry carrier inside the carrier reserve tank 93. In addition, the carrier transport member 931 transports the dry carrier from the front to the rear of the carrier reserve tank 93.

[0074] In this embodiment, the transport direction of the dry carrier in the carrier reserve tank 93 is aligned with the transport direction of the dry carrier in the carrier cartridge 91. In other words, the transport direction of the dry carrier in the carrier reserve tank 93 is aligned with the transport direction of the dry carrier in the carrier cartridge 91. In this embodiment, the transport direction of the dry carrier in the carrier cartridge 91 and the transport direction of the dry carrier in the carrier reserve tank 93 are aligned with the mounting and dismounting direction when the carrier cartridge 91 is mounted to and removed from the developer supply device .

[0075] An example of the carrier transport member 931 is a transport member having a rotating shaft extending in the front-rear direction of the carrier reserve tank 93 and a blade portion formed in a spiral shape around the rotating shaft. Further, a carrier detector 934 is provided inside the carrier reserve tank 93. The carrier detector 934 detects whether or not a dry carrier is present inside the carrier reserve tank 93. The carrier detector 934 is provided at a position closer to the carrier receiver 932 than the carrier input unit 95. The carrier detector 934 uses known technology such as a magnetic sensor, a piezoelectric sensor, or a photoelectric sensor.

[0076] The amount of dry carrier transported by the carrier transport member 931 is less than the amount of dry toner transported by the toner transport member 831 provided in the toner reserve tank 83 (see FIG. 5). One example of a method for making the transport amount by the carrier transport member 931 smaller than the transport amount by the toner transport member 831 is to make the diameters of the blades different. Specifically, for example, the diameter of the vane portion provided on the carrier transport member 931 may be made smaller than the diameter of the vane portion provided on the toner transport member 831.

[0077] Another example of a method for making the transport amount by the carrier transport member 931 smaller than the transport amount by the toner transport member 831 is to vary the installation intervals of the blade portions. Specifically, for example, the intervals at which the vanes of the carrier transport member 931 are provided may be set smaller than the intervals at which the vanes of the toner transport member 831 are provided.

[0078] As shown in FIG. 6, the carrier reserve tank 93 is provided with a carrier receiving portion 932 for receiving the dry carrier discharged from the carrier cartridge 91. The carrier receiving portion 932 is provided at a position facing the carrier discharging portion 913 provided in the carrier cartridge 91. The carrier receiving portion 932 is also provided in front of the carrier reserve tank 93. The carrier receiving portion 932 is also provided on the upper surface of the carrier reserve tank 93.

[0079] The carrier input unit 95 inputs the dry carrier in the carrier reserve tank 93 into the developing device (see FIG. 1). In this embodiment, the carrier input unit 95 is located vertically above the developing device . In this embodiment, the carrier input portion 95 is located vertically above the toner input portion 85 of the toner dispenser 82 . The carrier input unit 95 drops the dry carrier downward by gravity, and inputs the dry carrier into the developing device 14. More specifically, the carrier input unit 95 inputs the dry carrier into the developing device 14 by dropping the dry carrier from vertically above the toner input unit 85.

[0080] (Operation of Developer Supply Device 70) The operation of the developer supplying device 70 will now be described. The developer replenishing device 70 refills the developing device 14 with new dry toner and new dry carrier as the dry toner and dry carrier in the developing device 14 decrease. In the developing device 14, the dry toner is consumed as the toner image is formed on the photosensitive drum 11, and the amount of the dry toner decreases. Furthermore, the developing device 14 discharges the developer containing the dry carrier with reduced charging performance, thereby reducing the amount of dry toner and dry carrier. Generally, in the developing device 14, the amount of dry carrier reduced per unit time is smaller than the amount of dry toner reduced per unit time.

[0081] In this embodiment, for example, when the concentration of dry toner in the developing device 14 falls below a predetermined reference value, the developer replenishing device 70 replenishes dry toner to the developing device 14. Specifically, the developer supply device 70 supplies dry toner to the developing device 14 by rotating the toner stirring member 811 of the toner cartridge 81, the toner transport member 831 of the toner reserve tank 83, and the toner transport member 843 of the toner transport path 842.

[0082] When the dry toner is replenished, the dry toner is transported from the front to the rear of the toner cartridge 81 by the toner stirring member 811, and the dry toner flows into the toner reserve tank 83 of the toner dispenser . In the toner reserve tank 83, the dry toner is transported from the rear to the front of the toner reserve tank 83 by the toner transport member 831. As a result, the dry toner flows into the toner transport section .

[0083] In toner transport section 84, dry toner is transported from the front to the rear by toner transport member 843. As a result, the dry toner flows into toner input section 85. Then, the dry toner falls from the toner input portion 85 into the developing device 14, and the developing device 14 is replenished with the dry toner.

[0084] In this embodiment, when the amount of dry toner inside the toner cartridge 81 falls below a predetermined reference value, the toner cartridge 81 is replaced with a new toner cartridge 81 . In other words, in this embodiment, when the toner cartridge 81 becomes empty, the toner cartridge 81 is replaced with a new toner cartridge 81 .

[0085] In this embodiment, the toner reserve tank 83 contains the dry toner received from the toner cartridge 81. In other words, the toner reserve tank 83 accumulates the dry toner received from the toner cartridge 81. In this case, even if the toner cartridge 81 is removed for replacement, the dry toner stored in the toner reserve tank 83 can be used to continuously replenish the dry toner to the developing device 14.

[0086] In the developing device 14, the amount of dry toner depleted is greater than the amount of dry carrier depleted. Correspondingly, in the developer replenishing device 70, the amount of dry toner depleted is greater than the amount of dry carrier depleted. To meet this requirement, the developer supply device 70 of this embodiment is provided with two toner cartridges 81 and two toner reserve tanks 83. As a result, even if one of the toner cartridges 81 or toner reserve tank 83 becomes empty, the other toner cartridge 81 or toner reserve tank 83 can be used to continue supplying dry toner to the developing device 14.

[0087] In this embodiment, as described above, the direction in which the dry toner is transported in the toner cartridge 81 and the direction in which the dry toner is transported in the toner reserve tank 83 are opposite to each other. In this case, the developer replenishing device 70 can be made smaller than when the direction in which the dry toner is transported in the toner cartridge 81 and the direction in which the dry toner is transported in the toner reserve tank 83 are the same.

[0088] In addition, in this embodiment, the capacity of toner cartridge 81 and toner reserve tank 83 can be increased compared to a case in which the direction in which dry toner is transported in toner cartridge 81 and the direction in which dry toner is transported in toner reserve tank 83 are the same. Such an increase in size reduces the frequency of replacing the toner cartridge 81. Also, the supply of dry toner to the developing device 14 is less likely to be interrupted.

[0089] When the toner reserve tank 83 is empty when the toner cartridge 81 is replaced with a new one, a time lag occurs between when the new toner cartridge 81 is attached and when the dry toner is replenished to the developing device 14. In this embodiment, after a new toner cartridge 81 is attached, until the toner detection unit 834 (see FIG. 5) detects dry toner, the toner cartridge 81 and the toner reserve tank 83 perform an operation of transporting dry toner.

[0090] This operation is preferably performed before image forming apparatus 100 receives a print instruction from a user. In this embodiment, as shown in FIG. 5, toner detection unit 834 is provided at a position closer to toner receiving unit 832 than toner discharging unit 833 is. In this case, it is possible to more accurately detect whether the toner cartridge 81 is empty.

[0091] On the other hand, when the amount of dry carrier in the developing device 14 falls below a predetermined reference value, the developer replenishing device 70 replenishing the developing device 14 with dry carrier. Specifically, the developer supply device 70 rotates the carrier stirring member 911 and the carrier transport member 931 . As a result, the dry carrier is transported from the front to the rear of the carrier cartridge 91 , and the dry carrier flows into the carrier reserve tank 93 .

[0092] In the carrier reserve tank 93, the dry carrier is transported from the front to the rear of the carrier reserve tank 93. As a result, the dry carrier flows into the carrier input section 95. Then, the dry carrier falls from the carrier input portion 95 into the developing device 14, and the developing device 14 is replenished with the dry carrier.

[0093] Furthermore, in the developer replenishing device 70, when the amount of dry carrier contained in the carrier cartridge 91 falls below a predetermined reference value, the carrier cartridge 91 is replaced with a new carrier cartridge 91. In other words, when the carrier cartridge 91 becomes empty, the carrier cartridge 91 is replaced with a new carrier cartridge 91 .

[0094] In this embodiment, the carrier reserve tank 93 contains the dry carrier received from the carrier cartridge 91. In other words, the carrier reserve tank 93 accumulates the dry carrier received from the carrier cartridge 91. Therefore, even if the carrier cartridge 91 is removed in order to replace it, for example, the supply of dry carrier to the developing device 14 can be continued.

[0095] When the carrier reserve tank 93 is empty when the carrier cartridge 91 is replaced with a new carrier cartridge 91, a time lag occurs between when the new carrier cartridge 91 is attached and when the dry carrier is replenished to the developing device 14. When a new carrier cartridge 91 is attached, an operation of transporting the dry carrier is performed inside the carrier cartridge 91 and the carrier reserve tank 93 until the carrier detection unit 934 (see FIG. 6) detects the dry carrier.

[0096] This operation is preferably performed before image forming apparatus 100 receives a print instruction from a user. In this embodiment, the carrier detection unit 934 is provided at a position closer to the carrier receiving unit 932 than the carrier input unit 95 is. Therefore, in this embodiment, it is possible to accurately detect whether or not the carrier cartridge 91 is empty.

[0097] In this embodiment, the volume of the carrier reserve tank 93 is smaller than the volume of the toner reserve tank 83 . In this embodiment, the amount of dry carrier reduced in the developer replenishing device 70 is smaller than the amount of dry toner reduced in the developer replenishing device 70 . Therefore, even if the volume of the carrier reserve tank 93 is made smaller than the volume of the toner reserve tank 83 as in this embodiment, problems such as interruption of the supply of dry carrier to the developing device 14 are unlikely to occur.

[0098] Furthermore, as in this embodiment, when the volume of the carrier reserve tank 93 is made smaller than the volume of the toner reserve tank 83, the volume of the carrier dispenser 92 can be reduced, and the developer supply device 70 can be reduced in size.

[0099] Furthermore, in this embodiment, the length of the carrier reserve tank 93 is shorter than the length of the toner reserve tank 83. More specifically, when comparing the lengths along the attachment / detachment direction of the toner cartridge 81, the length of the carrier reserve tank 93 is shorter than the length of the toner reserve tank 83. In this case, the transport distance of the dry carrier in the carrier reserve tank 93 is shorter than when the length of the carrier reserve tank 93 is equal to or longer than the length of the toner reserve tank 83 . In this case, the volume of the carrier dispenser 92 is smaller than when the length of the carrier reserve tank 93 is equal to or greater than the length of the toner reserve tank 83 .

[0100] In this embodiment, the amount of dry carrier transported by the carrier transport member 931 provided in the carrier reserve tank 93 is smaller than the amount of dry toner transported by the toner transport member 831 provided in the toner reserve tank 83 . In this embodiment, the amount of dry carrier replenished to the developing device 14 is less than the amount of dry toner replenished to the developing device 14 .

[0101] Therefore, even if the amount of dry carrier transported by the carrier transport member 931 provided in the carrier reserve tank 93 is made less than the amount of dry toner transported by the toner transport member 831 provided in the toner reserve tank 83, a situation such as a delay in the supply of dry carrier to the developing device 14 is unlikely to occur. In addition, when the amount of dry carrier transported by the carrier transport member 931 provided in the carrier reserve tank 93 is smaller than the amount of dry toner transported by the toner transport member 831 provided in the toner reserve tank 83, the diameter of the blade portion of the carrier transport member 931 can be made smaller. In this case, the carrier transport member 931 can be made smaller, and therefore the developer supply device 70 can be made smaller.

[0102] In this embodiment, as described above, the transport direction of the dry carrier in the carrier cartridge 91 and the transport direction of the dry carrier in the carrier reserve tank 93 are aligned. This allows the transport distance of the dry carrier in the carrier reserve tank 93 to be shorter than when, for example, the transport direction of the dry carrier in the carrier cartridge 91 and the transport direction of the dry carrier in the carrier reserve tank 93 are opposite.

[0103] In this embodiment, the length of the carrier cartridge 91 in the mounting / removal direction is shorter than the length of the toner cartridge 81 in the mounting / removal direction. As shown in FIG. 3, the rear end of the carrier cartridge 91 is located forward of the rear end of the toner cartridge 81 with respect to the developer supply device 70 . As a result, in this embodiment, it is possible to provide the carrier dispenser 92 in an area where there is a difference in length between the carrier cartridge 91 and the toner cartridge 81, and the developer supply device 70 can be made compact. In other words, as shown in FIG. 3, it is possible to provide the carrier dispenser 92 behind the carrier cartridge 91, and the developer supply device 70 can be made compact.

[0104] Moreover, in general, a dry carrier has a larger specific gravity than a dry toner. By making the length along the mounting / removal direction of the carrier cartridge 91 containing a dry carrier with a high specific gravity shorter than the length along the mounting / removal direction of the toner cartridge 81 containing a dry toner with a low specific gravity, the operability when mounting / removing the carrier cartridge 91 is improved. Specifically, the length by which the user moves the carrier cartridge 91 in the mounting / removing direction can be made smaller than the length by which the user moves the toner cartridge 81 in the mounting / removing direction, improving operability when mounting and removing the carrier cartridge 91.

[0105] In the developer supply device 70 of this embodiment, the carrier cartridge 91 is positioned vertically below the toner cartridge 81, as shown in FIG. Specifically, the portion of the carrier cartridge 91 that is located at the bottom in the vertical direction is located vertically lower than the portion of the toner cartridge 81 that is located at the bottom in the vertical direction. In other words, the lowermost part of the carrier containing portion 530 in the vertical direction is located vertically lower than the lowermost part of the toner containing portion 630 in the vertical direction.

[0106] Furthermore, in this embodiment, the central axis of the carrier cartridge 91 is positioned vertically below the central axis of the toner cartridge 81 . Furthermore, in this embodiment, the portion of the carrier cartridge 91 that is located at the top in the vertical direction is located vertically below the portion of the toner cartridge 81 that is located at the top in the vertical direction. In this manner, in this embodiment, the carrier cartridge 91 that accommodates the dry carrier having a large specific gravity is positioned vertically below the toner cartridge 81 that accommodates the dry toner having a small specific gravity. In this case, the user can install or remove the carrier cartridge 91 vertically below the position where the toner cartridge 81 is installed or removed.

[0107] In this embodiment, the carrier dispenser 95 (see FIG. 6) dispenses the dry carrier into the developing device 14 by dropping the dry carrier from a position vertically above the toner dispenser 85. In this way, when the dry carrier having a higher specific gravity is charged vertically from above than the dry toner having a lower specific gravity, the dry carrier dropping from vertically above comes into contact with the dry toner in toner charging portion 85 . This breaks down the dry toner in the toner input unit 85, suppressing clogging of the dry toner. Also, the dry toner and the dry carrier are easily mixed, reducing unevenness in the concentration of the dry toner in the developing device 14.

[0108] In this embodiment, the dry toner is directly fed from the toner feed section 85 to the developing device 14, and the dry carrier is directly fed from the carrier feed section 95 to the developing device 14, but the present invention is not limited to this. For example, a dry toner may be supplied from a toner input unit 85 and a dry carrier may be input from a carrier input unit 95 to a common transport path leading to the developing device 14 .

[0109] In this case, the dry toner and the dry carrier pass through this common transport path toward the developing device 14 . In this case, it is preferable to provide the toner input unit 85 on the upstream side and the carrier input unit 95 on the downstream side in the transport direction of the transport path. In this case, it is preferable to supply the dry carrier from the carrier input unit 95 to the transport path from above the transport path.

[0110] In the above, it has been described that the toner cartridge 81 is removed by pulling the toner cartridge 81 forward from the developer supply device 70, and that the toner cartridge 81 is installed by pushing the toner cartridge 81 backward from the developer supply device 70. However, without being limited to this, the toner cartridge 81 may be removed from the developer supply device 70 by pulling it out to the rear of the developer supply device 70, and may be attached to the developer supply device 70 by pushing it into the front of the developer supply device 70.

[0111] In addition, in the above, it has been described that the carrier cartridge 91 is removed by pulling the carrier cartridge 91 toward the front of the developer supply device 70, and that the carrier cartridge 91 is attached by pushing the carrier cartridge 91 toward the rear of the developer supply device 70. However, without being limited to this, the carrier cartridge 91 may be removed from the developer supply device 70 by pulling it out to the rear of the developer supply device 70, and may be attached to the developer supply device 70 by pushing it into the front of the developer supply device 70.

[0112] In the present embodiment, as described above, toner agitation member 811 (see FIG. 5) used for transporting dry toner is provided inside toner cartridge 81, but toner agitation member 811 is not essential. A spiral protrusion may be provided on the inner peripheral surface of the toner cartridge 81, and the toner cartridge 81 may be rotated in the circumferential direction to transport the dry toner. Similarly, the carrier cartridge 91 may be provided with a spiral projection on the inner peripheral surface thereof, and the carrier cartridge 91 may be rotated in the circumferential direction to transport the dry carrier.

[0113] In the above, the case where toner detection unit 834 (see FIG. 5) is provided at a position closer to toner receiving unit 832 than toner discharging unit 833 has been described. However, the present invention is not limited to this, and the toner detection unit 834 may be provided at a position closer to the toner discharge unit 833 than the toner receiving unit 832. In this case, it becomes easy to replenish the dry toner to a position closer to the toner discharge unit 833 of the toner reserve tank 83.

[0114] In the above, the case where the carrier detection unit 934 (see FIG. 6) is provided at a position closer to the carrier receiving unit 932 than the carrier input unit 95 is described. However, the present invention is not limited to this, and the carrier detection unit 934 may be provided at a position closer to the carrier input unit 95 than the carrier receiving unit 932. In this case, it becomes easy to supply the dry carrier to a position of the carrier reserve tank 93 close to the carrier input unit 95.

[0115] FIG. 10 is a schematic diagram showing functions of the image forming apparatus 100 shown in FIG. In FIG. 10, the image forming unit 200 and the developer supply device 70 are shown, and other elements are omitted. As shown in FIG. 10, the image forming apparatus 100 of this embodiment is provided with a carrier supply mechanism 500 that supplies dry carrier to the multiple developing devices 14 provided. In this embodiment, a toner supply mechanism 600 is provided to supply dry toner to the multiple developing devices 14 provided. In this embodiment, the carrier supply mechanism 500 and the toner supply mechanism 600 are realized by a plurality of the developer replenishing devices 70 described above.

[0116] In this embodiment, the carrier supply mechanism 500 is provided with six carrier supply units 510 provided corresponding to the respective developing devices 14. In other words, the carrier supply mechanism 500 is provided with six carrier supply units 510 provided corresponding to the respective image forming sections 200. Further, the toner supply mechanism 600 is provided with six toner supply units 610 provided corresponding to the respective developing devices 14. In other words, the toner supply mechanism 600 is provided with six toner supply units 610 provided corresponding to the respective image forming sections 200.

[0117] Each of the toner supply units 610 is provided with a toner storage section 630 and a toner replenishing section 640 . In this embodiment, a toner storage unit 630 is provided at a location separate from the developing device 14. In this embodiment, the toner storage unit 630 stores dry toner that is newly supplied from outside the image forming apparatus 100. In this embodiment, new dry toner is supplied from the toner storage unit 630 to the corresponding developing device 14. More specifically, in this embodiment, the toner supply unit 640 receives dry toner from the toner storage unit 630 and supplies the dry toner to the corresponding developing device 14 .

[0118] Each of the carrier supply units 510 is provided with a carrier storage section 530 and a carrier replenishing section 540 . In this embodiment, a carrier container 530 is provided at a location separate from the developing device 14. In this embodiment, the carrier accommodating section 530 accommodates a dry carrier that is newly supplied from outside the image forming apparatus 100. In this embodiment, a new dry carrier is supplied from the carrier accommodating section 530 to the corresponding developing device 14. More specifically, in this embodiment, the carrier supply unit 540 receives the dry carrier from the carrier storage unit 530 and supplies the dry carrier to the corresponding developing device 14 .

[0119] In this embodiment, the length of the carrier supply unit 540 is shorter than the length of the toner supply unit 640 . More specifically, when comparing the lengths along the mounting direction of toner cartridge 81, the length of carrier supply section 540 along this mounting direction is shorter than the length of toner supply section 640 along this mounting direction. More specifically, the sum of the lengths of the portions of carrier supply unit 540 along the mounting direction is shorter than the sum of the lengths of the portions of toner supply unit 640 along the mounting direction.

[0120] In addition, in this embodiment, when comparing the cross-sectional areas in a plane perpendicular to the mounting direction of toner cartridge 81, the cross-sectional area of ​​the portion of carrier supply section 540 extending in this mounting direction is smaller than the cross-sectional area of ​​the portion of toner supply section 640 extending in this mounting direction. In this embodiment, the length of the carrier containing section 530 is shorter than the length of the toner containing section 630 when the lengths of the toner cartridge 81 in the mounting direction are compared.

[0121] In this embodiment, the volume of the space in the carrier supply mechanism 500 through which the dry carrier passes is smaller than the volume of the space in the toner supply mechanism 600 through which the dry toner passes. "The volume of the space in the carrier supply mechanism 500 through which the dry carrier passes" refers to the volume obtained by adding (summing) the volume of the portion of the carrier supply unit 510 provided for each developing device 14 through which the dry carrier passes. In addition, "the volume of the space in the toner supply mechanism 600 through which the dry toner passes" refers to the volume obtained by adding (summing) the volumes of the portions of the toner supply units 610 provided for each developing device 14 through which the dry toner passes.

[0122] Here, "the volume of the portion of the carrier supply unit 510 through which the dry carrier passes" includes not only the volume of the carrier replenishing section 540 but also the volume of the carrier accommodating section 530, and "the portion of the carrier supply unit 510 through which the dry carrier passes" refers to the portion from the carrier accommodating section 530 to the developing device 14. In addition, the "volume of the portion of toner supply unit 610 through which dry toner passes" includes not only the volume of toner replenishing section 640 but also the volume of toner storage section 630, and the "portion of toner supply unit 610 through which dry toner passes" refers to the portion from toner storage section 630 to developing device 14.

[0123] In addition, the "volume of the portion of the carrier supply unit 510 through which the dry carrier passes" includes not only the volume of the portion actually occupied by the dry carrier, but also the volume of the space located above the dry carrier where no dry carrier is present. Similarly, the "volume of the portion of the toner supply unit 610 through which the dry toner passes" includes not only the volume of the portion actually occupied by the dry toner, but also the volume of the space located above the dry toner where no dry toner is present.

[0124] In addition, "the volume of the portion of the carrier supply unit 510 through which the dry carrier passes" refers to the volume assuming that no components used to transport the dry carrier, such as the carrier stirring member 911 and the carrier transport member 931 shown in Figure 6, are provided. In addition, "the volume of the portion of toner supply unit 610 through which dry toner passes" refers to the volume assuming that no members used to transport dry toner, such as toner stirring member 811, toner transport member 831, and toner transport member 843 shown in Figures 5 and 6, are provided.

[0125] In addition, in this embodiment, the sum of the amount of dry carrier supplied to the developing device 14 and the amount of dry carrier discharged from the developing device 14 is smaller than the amount of dry toner consumed when a toner image is formed in the image forming unit 200. Here, a carrier supply amount, which is the amount of dry carrier supplied per unit time to each developing device 14, is assumed. Also, a carrier discharge amount, which is the amount of dry carrier discharged per unit time from each developing device 14, is assumed.

[0126] Also, a toner consumption amount, which is the amount of dry toner consumed per unit time when a toner image is formed in each image forming section 200, is assumed. In this embodiment, the value obtained by multiplying the sum of the carrier supply amount and the carrier discharge amount by the number of image forming units 200 installed (in this embodiment, "6") is smaller than the value obtained by multiplying the toner consumption amount by this number. When such a relationship is satisfied, the volume occupied by the carrier supply mechanism 500 can be made smaller than when such a relationship is not satisfied, and the image forming apparatus 100 can be made more compact.

[0127] In other words, in this embodiment, the sum of the carrier supply amount and the carrier discharge amount is smaller than the amount of dry toner supplied to the outside of the developing device 14 through the opening 143 (see FIG. 8). Here, when a toner image is formed in image forming section 200, a supply toner amount is assumed to be the amount of dry toner supplied to the outside of developing device 14 through opening 143 per unit time. In this embodiment, the value obtained by multiplying the sum of the carrier supply amount and the carrier discharge amount by the number of installed image forming units 200 is smaller than the value obtained by multiplying the supplied toner amount by this number. With this relationship, as described above, the volume occupied by the carrier supply mechanism 500 can be reduced, and the image forming apparatus 100 can be made more compact.

[0128] Further, the amount of dry toner consumed when forming an image on A3 size paper will be compared with the amount of dry toner consumed when forming an image on paper of size A3 or larger. For example, let us compare the amount of dry toner consumed when forming an image at 100% image density over the entire surface of an A3 size sheet of paper with the amount of dry toner consumed when forming an image at 100% image density over the entire surface of a sheet of paper larger than A3 size. Specifically, we will compare the amounts for A2 size, A1 size, A0 size, B3 size, B2 size, B1 size, and B0 size. The length of the short side l, the length of the long side L, and the area M of each piece of paper are A2 size (l = 420 mm, L = 594 mm, M = 249,480 mm 2 ), A1 size (l = 594mm, L = 841mm, M = 449,554mm 2), A0 size (l = 841 mm, L = 1,189 mm, M = 999,949 mm 2 ), B3 size (l = 364 mm, L = 515 mm, M = 187,460 mm 2 ), B2 size (l = 515mm, L = 728mm, M = 374,920mm 2 ), B1 size (l = 728 mm, L = 1,030 mm, M = 749,840 mm 2 ), B0 size (l = 1,030mm, L = 1,456mm, M = 1,499,680mm 2 ), so if the amount of dry toner consumed for A3 size is taken as 1, then the amount of dry toner consumed for A2 size is 2 times, the amount of dry toner consumed for A1 size is 4 times, the amount of dry toner consumed for A0 size is 8 times, the amount of dry toner consumed for B3 size is 1.5 times, the amount of dry toner consumed for B2 size is 3 times, the amount of dry toner consumed for B1 size is 6 times, and the amount of dry toner consumed for B0 size is 12 times. The same is true for the amount of dry toner supplied to the developing device 14, so if the amount of dry toner consumed for A3 size is taken as 1, then the amount of dry toner consumed for A2 size is 2 times, the amount of dry toner consumed for A1 size is 4 times, the amount of dry toner consumed for A0 size is 8 times, the amount of dry toner consumed for B3 size is 1.5 times, the amount of dry toner consumed for B2 size is 3 times, the amount of dry toner consumed for B1 size is 6 times, and the amount of dry toner consumed for B0 size is 12 times. Also, the more dry toner consumed, the more dry carrier consumed. In the case where the axial length L of the developing sleeve 145A is equal to or longer than the length of the long side of the A3 size as in this embodiment, the volume occupied by the carrier supply mechanism 500 can be reduced, thereby enabling the miniaturization of the image forming apparatus 100. Furthermore, in the case where at least five image forming units 200 are provided, the volume occupied by the carrier supply mechanism 500 can be reduced, thereby enabling the miniaturization of the image forming apparatus 100.

[0129] In this embodiment, as shown in FIG. 10, a toner storage unit 630 for storing dry toner newly supplied from outside the image forming apparatus 100 is provided at a location separate from the developing device 14. In this embodiment, a toner container 630 is provided corresponding to each of the image forming units 200. In this embodiment, new dry toner is supplied from the toner container 630 to the corresponding developing device 14. In this embodiment, a toner supply unit 640 is provided corresponding to each of the image forming units 200. The toner supply unit 640 receives dry toner from the toner storage unit 630, and supplies the dry toner to the corresponding developing device 14.

[0130] In this embodiment, a carrier container 530 for accommodating a dry carrier newly supplied from outside the image forming apparatus 100 is provided at a location separate from the developing device 14. In this embodiment, a carrier container 530 is provided so as to correspond to each of the image forming units 200. In this embodiment, new dry carrier is supplied from the carrier container 530 to the corresponding developing device 14. In this embodiment, a carrier supply unit 540 is provided corresponding to each of the image forming units 200. The carrier supply unit 540 receives the dry carrier from the carrier storage unit 530 and supplies the dry carrier to the corresponding developing device 14.

[0131] 10, a case has been described in which new dry toner is supplied to toner accommodating unit 630 by installing toner cartridge 81 that accommodates dry toner in toner accommodating unit 630. In this case, new dry toner is supplied to developing device 14 from toner cartridge 81 installed in toner accommodating unit 630. As described above, the toner storage unit 630 may be configured as a storage chamber that stores dry toner. In this case, new dry toner is supplied from the transfer container to the storage chamber, and the dry toner is supplied to the toner storage unit 630.

[0132] In this embodiment, a carrier cartridge 91, which is an example of a container that contains a dry carrier, is placed in the carrier container 530, whereby new dry carrier is supplied to the carrier container 530. However, the present invention is not limited to this, and as described above, the carrier storage section 530 may be configured as a storage chamber for storing the dry carrier. In this case, a new dry carrier is supplied from the transfer container to this storage chamber, and the dry carrier is supplied to the carrier storage section 530.

[0133] In this embodiment, the sum of the volumes of the multiple carrier containing sections 530 is smaller than the sum of the volumes of the multiple toner containing sections 630. In other words, the total value obtained by adding up the volumes of the multiple carrier containing sections 530 is smaller than the total value obtained by adding up the volumes of the multiple toner containing sections 630.

[0134] In this embodiment, the sum of the volumes of the multiple carrier supply units 540 is smaller than the sum of the volumes of the multiple toner supply units 640. In other words, the total value obtained by adding up the volumes of each of the multiple carrier supply units 540 is smaller than the total value obtained by adding up the volumes of each of the multiple toner supply units 640.

[0135] In addition, in this embodiment, the sum of the respective post-addition volumes, which are the combined volumes of the carrier supply section 540 and the carrier storage section 530, is smaller than the sum of the respective post-addition volumes, which are the combined volumes of the toner supply section 640 and the toner storage section 630. More specifically, a first sum is assumed to be a post-addition volume that is the combined volume of the carrier supply section 540 and the carrier accommodating section 530 and that is the sum of the post-addition volumes obtained for each carrier supply unit 510. Also, a second sum is assumed, which is the sum of the volumes of the toner replenishing section 640 and the toner storage section 630 and is the sum of the volumes of the toner supply units 610 after addition. In this embodiment, the first sum is smaller than the second sum.

[0136] In this embodiment, when the volume of the carrier supplying section 540 alone is compared with the volume of the toner supplying section 640 alone, the volume of the carrier supplying section 540 is smaller than the volume of the toner supplying section 640 alone. In this embodiment, when the volume of the carrier accommodating portion 530 alone is compared with the volume of the toner accommodating portion 630 alone, the volume of the carrier accommodating portion 530 is smaller than the volume of the toner accommodating portion 630 alone.

[0137] FIG. 11 is a diagram showing another example of the configuration of the image forming apparatus 100. In FIG. In this configuration example, a plurality of carrier movement paths RC extending from a common carrier accommodating portion 530 toward a plurality of developing devices 14 are provided. In this embodiment, a portion of the carrier supply mechanism 500 through which the dry carrier passes is a carrier movement path RC, which is a movement path of the dry carrier. In this configuration example, a plurality of carrier movement paths RC are provided. In addition, in this configuration example, the plurality of carrier movement paths RC extend from a common carrier storage portion 530 toward the plurality of developing devices 14.

[0138] More specifically, in this configuration example, the carrier movement path RC branches off on the way from the carrier accommodating portion 530 to the developing device 14, and this branching provides a plurality of carrier movement paths RC. Each of the plurality of carrier movement paths RC heads toward a different developing device 14. Note that the carrier movement path RC is not limited to being branched in this manner, and each of the carrier movement paths RC may be provided independently as shown in FIG. 12 (a diagram showing another example of the configuration of the image forming apparatus 100). In this configuration example shown in FIG. 12, each of the independently provided carrier movement paths RC is connected to a common carrier receiving section 530. In the configuration example shown in FIG.

[0139] In providing the common carrier receiving section 530, there is no particular limit to the number of the carrier receiving section 530. The common carrier receiving section 530 is not limited to one, and a plurality of the common carrier receiving sections 530 may be provided. When a common carrier container 530 is provided, the number of carrier containers 530 may be smaller than the number of developing devices 14 . For example, two carrier containers 530 may be provided, and the carrier movement paths RC may extend from each of the two carrier containers 530 to the three developing devices 14.

[0140] In this configuration example shown in FIGS. 11 and 12, as in the above, a toner cartridge 81 is placed in toner containing section 630, whereby new dry toner is supplied to toner containing section 630. In this configuration example, similarly to the above, a carrier cartridge 91 is placed in the carrier storage unit 530, whereby a new dry carrier is supplied to the carrier storage unit 530. However, the present invention is not limited to this, and similarly to the above, the toner storage unit 630 may be configured as a storage chamber for storing dry toner, and the carrier storage unit 530 may also be configured as a storage chamber for storing dry carrier.

[0141] FIG. 13 is a diagram showing another example of the configuration of the image forming apparatus 100. In FIG. In this configuration example, a developer container 730 is provided corresponding to each of the developing devices 14. Specifically, in this configuration example, the above-mentioned two containers, the carrier container 530 and the toner container 630, are not provided. In this configuration example, one developer container 730 is provided corresponding to each of the developing devices 14. Furthermore, one developer supply section 740 is provided corresponding to each of the developing devices 14. The developer supply unit 740 receives the developer from the developer container 730 and supplies the developer to the corresponding developing device 14 .

[0142] In this configuration example, a developer cartridge 98 containing a developer made of dry toner and dry carrier is installed in the developer storage unit 730. In other words, in this configuration example, a developer cartridge 98 containing a mixture of dry toner and dry carrier is installed in the developer storage unit 730. The developer cartridge 98 supplies dry toner and dry carrier to the corresponding developing device 14 .

[0143] In this configuration example, the type of dry toner contained in each developer cartridge 98 is different for each developer cartridge 98. Furthermore, the dry carrier does not differ for each developer cartridge 98, and each developer cartridge 98 contains a common dry toner. The type of dry carrier contained in each developer cartridge 98 may be different.

[0144] In this configuration example, it is not necessary to provide either the space for installing the carrier containing section 530 or the space for installing the toner containing section 630, and the image forming apparatus 100 can be made smaller. As described above, the developer accommodating portion 730 is not limited to a form in which the developer cartridge 98 is installed, and may be configured as an accommodating chamber to which only the developer is supplied, as described above.

[0145] FIG. 14 is a diagram showing another example of the configuration of the image forming apparatus 100. In FIG. FIG. 14 shows a modified example of the image forming apparatus 100 shown in FIG. In this configuration example shown in FIG. 14, the developer supply section 740 shown in FIG. 13 is not provided, and a developer container 730 is directly connected to the developing device 14. In the configuration example shown in FIG. The developer supply unit 740 is not essential, and the developer may be directly supplied from the developer container 730 to the developing device 14 . In this configuration example shown in FIG. 14, similarly to the above, a developer cartridge 98 may be installed in the developer accommodating section 730 to supply developer to the developer accommodating section 730, or the developer accommodating section 730 may be a storage chamber to which only developer is supplied.

[0146] This direct connection configuration may also be applied to the image forming apparatus 100 shown in FIGS. Specifically, in the image forming apparatus 100 shown in FIG. 10, the toner supply section 640 and the carrier supply section 540 may be omitted, and the developing device 14 and the toner storage section 630 may be directly connected, and the developing device 14 and the carrier storage section 530 may be directly connected. In addition, in the image forming apparatus 100 shown in FIG. 11, the toner supply unit 640 may be omitted, and the developing device 14 and the toner storage unit 630 may be directly connected to each other.

[0147] FIG. 15 is a diagram showing another example of the configuration of the image forming apparatus 100. In FIG. This configuration example does not include the above-described carrier accommodating section 530, toner accommodating section 630, and developer accommodating section 730. Also, this configuration example does not include the above-described carrier supply section 540, toner supply section 640, and developer supply section 740. 15, the developer is directly supplied to the developing device 14 from a transfer container for transferring the developer by manual operation by a user. After the developer is supplied to the developing device 14, the transfer container is removed.

[0148] The supply of developer to the developing device 14 does not have to be manual, but may be automatic. Specifically, for example, a transport member for transporting the developer may be installed inside the transport container, and after the transport container is installed in the developing device 14, the transport member may be operated to automatically supply the developer from the transport container to the developing device 14. In this case, after the developer is supplied to the developing device 14, the transport container is removed.

[0149] Further, although the configuration has been described here in which the developer, which is a mixture of dry carrier and dry toner, is directly supplied to the developing device 14, the supply mode is not limited to this. For example, a transport container containing only the dry carrier and a transport container containing only the dry toner may be prepared, and the dry toner and the dry carrier may be supplied to the developing device 14 separately.

[0150] In addition, the configurations described above are not limited to the above-mentioned embodiments and their modifications, and can be modified without departing from the spirit of the invention. In other words, it is understood that various modifications of the form and details are possible without departing from the spirit and scope of the claims. For example, some of the components described above may be omitted, or other functions may be added to the components described above. Further, although multiple configuration examples have been described above, the configuration included in one configuration example may be interchanged with the configuration included in another configuration example, or the configuration included in one configuration example may be added to another configuration example. [Explanation of symbols]

[0151] 11...photosensitive drum, 14...developing device, 20...secondary transfer section, 50...paper, 81...toner cartridge, 100...image forming apparatus, 145A...developing sleeve, 200...image forming section, 500...carrier supply mechanism, 530...carrier storage section, 540...carrier replenishing section, 600...toner supply mechanism, 630...toner storage section, 640...toner replenishing section, RC...carrier movement path

Claims

1. An image forming apparatus for forming an image on a recording medium, at least five image forming stations each including an image carrier and using a dry toner to form an image on the image carrier to be transferred to a recording medium; a developing device provided in each of the at least five image forming units, to which a dry toner and a dry carrier are supplied, the developing device including a dry toner attachment portion having a length equal to or greater than the length of a long side of an A3 size and to which the dry toner is attached, the developing device causing the dry toner attached to the dry toner attachment portion to adhere to the image carrier; a toner supply mechanism that is attached to the image forming apparatus and that transports dry toner from a toner storage container that stores dry toner to the developing device and supplies the dry toner to the developing device; a carrier supply mechanism that is attached to the image forming apparatus and transports a dry carrier from a carrier storage container that stores a dry carrier to the developing device, and supplies the dry carrier to the developing device; Equipped with the amount of dry toner supplied to the developing device is greater than the amount of dry carrier supplied to the developing device; the path along which the dry toner discharged from the toner discharge portion provided in the toner storage container travels toward the developing device is from a location where the toner discharge portion is provided toward an upstream side in a mounting direction when the toner storage container is mounted, and then travels toward a downstream side in the mounting direction to reach the developing device; the dry carrier discharged from the carrier discharge portion provided in the carrier storage container does not travel toward the upstream side in the mounting direction when the toner storage container is mounted, but travels toward the downstream side in the mounting direction from a location where the carrier discharge portion is provided to reach the developing device; Image forming device.

2. The carrier storage container and the toner storage container are configured to be individually mounted on the image forming apparatus, 2 . The image forming apparatus according to claim 1 , wherein the carrier storage container is shorter than the toner storage container in the mounting direction.

3. An image forming device as described in claim 2, wherein, when the carrier storage container and the toner storage container are attached to the image forming device, an end of the carrier storage container that is located downstream in the attachment direction is located upstream in the attachment direction of an end of the toner storage container that is located downstream in the attachment direction.

4. a transfer unit that transfers the image formed by the image forming unit onto a recording medium; an inversion mechanism for inverting a recording medium having an image transferred to one side thereof by the transfer unit and supplying the recording medium to the transfer unit; The image forming apparatus according to claim 1 , further comprising:

5. An image forming apparatus as described in claim 1, wherein the volume of the space in the portion of the carrier supply mechanism through which the dry carrier passes is smaller than the volume of the space in the portion of the toner supply mechanism through which the dry toner passes.

6. An image forming device as described in claim 1, wherein the value obtained by multiplying the sum of the amount of dry carrier supplied per unit time to each of the developing devices and the amount of dry carrier discharged per unit time from each of the developing devices by the number of the image forming units installed is smaller than the value obtained by multiplying the amount of dry toner consumed per unit time when an image is formed in each of the image forming units by the number of the image forming units installed.

7. 2. The image forming apparatus according to claim 1, wherein the cross-sectional area of ​​the path through which the dry carrier passes is smaller than the cross-sectional area of ​​the path through which the dry toner passes when the cross-sectional areas of the toner storage container are compared in a plane perpendicular to the mounting direction.

8. the toner supply mechanism supplies the dry toner to the developing device by dropping the dry toner, and the toner supply mechanism is provided with a toner dropping section through which the dry toner drops toward the developing device; the carrier supply mechanism drops the dry carrier from above vertically to supply the dry carrier to the developing device, and the carrier supply mechanism is provided with a carrier drop section through which the dry carrier drops toward the developing device; 2. The image forming apparatus according to claim 1, wherein the carrier drop portion is located directly above the toner drop portion, and the falling dry carrier reaches the toner drop portion.

9. An image forming device as described in claim 1, wherein the vertical lowest portion of the carrier storage container mounted on the image forming device is located vertically lower than the vertical lowest portion of the toner storage container mounted on the image forming device.

Images